JPH08274700A - Radio communication system - Google Patents

Abstract

PURPOSE: To reserve a wide band width to transmit data at a high speed, to reduce the transmission power, and to suppress the occurrence of communication hindrance by setting the down line from a base station to a terminal to the transmission speed higher than that of the up line from the terminal to the base station. CONSTITUTION: A radio base station 1001 and a portable radio terminal 1003 are so constituted that they can use a down line (high-speed down radio communication line) of 100Mbps transmission speed using the submillimeter wave band or the millimeter wave band and an up line (low-speed up radio communication line) 1006 of 30kbps transmission speed using the micro wave band to communicate with each other. A directional antenna is used for reception of the up line 1004 on the side of a radio repeating station 1002. Since the directional antenna is used, the transmission side can efficiently transmit information to the reception side, and the reception side can efficiently receive the information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an SDL (Super-hi) equipped with a downlink for performing transmission at a higher speed than a uplink from a radio communication terminal to a radio base station in a radio transmission line.
The present invention relates to a wireless communication system that performs gh-speed Down-Link) transmission.

[0002]

2. Description of the Related Art A wired communication system is a system used for communication with terminals whose installation positions are fixed, whereas wireless communication is used for communication with moving terminals, remote islands, remote areas,
It is a system used for communication when communication cables cannot be used in the air or in space, and in recent years, its importance has rapidly expanded.

By the way, in wireless communication, various attempts have been made to widen the bandwidth of the line because of the demand for high-speed transmission of extremely large amount of data such as image transmission. As the world goes toward multimedia, widening the band of wireless communication is a common problem not only in mobile communication but also in wireless LAN (local area network) and various other wireless services.

By the way, even if it is said that the band of wireless communication is broadened, an easy-to-use frequency band cannot be used because of the existing frequency allocation. Therefore, the usable frequency band is limited to a short wavelength band. . The frequency band with a short wavelength is specifically a high frequency band higher than the microwave band, and the higher the frequency band, the greater the attenuation of radio waves and the shorter the propagation distance. It is vulnerable to things and you can not communicate unless you can see it.

From this point of view, it is preferable to use the microwave band if possible, however, in view of image transmission and the like, the desired transmission rate is about 100 Mbps, and the frequency bandwidth required for this is 100 MHz. It also becomes a degree.

However, it is extremely difficult for one user to occupy such a wide bandwidth in the microwave band because the radio waves are public ones and it is not practical.

Therefore, in order to secure a wide bandwidth, it is necessary to use a quasi-millimeter wave band or a millimeter wave band having a high directivity, or to use infrared rays having no limitation on the frequency width and the like.

However, millimeter wave radio waves and infrared rays must be used in line of sight due to the nature of their propagation. Therefore, when communicating between the base station BS and the terminal PT,
If the shield exists between the base station and the terminal, the characteristics of the communication transmission are significantly deteriorated, and the communication is often disabled.

FIG. 13 shows a conventional example of a wireless communication system implemented by microwaves or the like. In this system,
It is assumed that the wireless base station 3101 and the wireless terminal 3102 are shielded by a partition 3103 which is a shield. Therefore, the wireless base station 3101 and the wireless terminal 3102 are not in a line-of-sight state, but when a relatively low frequency band such as microwaves is used, there is a wraparound of radio waves,
Since there is no communication obstacle even if no special measures are taken to avoid obstacles due to the obstacle, communication between the base station and the terminal can be performed without any trouble.

On the other hand, in the case of millimeter waves and infrared rays, as shown in FIG. 14, good quality communication cannot be performed unless the base station 3201 and the terminal 3202 are in sight because of their straightness, and the base station 3201 and the terminal 3202 cannot communicate with each other. There was a problem that the terminal could not be installed in a place located in the non-line-of-sight region 3204 because it was blocked by the shield 3203.

Furthermore, the attenuation due to the distance in the millimeter wave band is large, and when the distance between the base station and the mobile station is several tens of meters, radio waves are radiated by the omnidirectional antenna. There is also a problem that a very large transmission power is required in order to be able to mutually obtain a predetermined communication quality, which is a major obstacle in terms of energy saving measures on the terminal side.

[0012]

The wireless communication is not limited to mobile communication, but in recent years, its application to LAN and the like has been widespread, and the band has been widened with the demand for image transmission. When a wireless communication system is required to have a wide band, it is practically impossible to occupy a wide band in the microwave band because it is only possible to use the frequency band higher than the microwave because of frequency allocation. From quasi-millimeter wave or millimeter wave,
Alternatively, there is no choice but to use a frequency band having a strong directivity such as infrared rays.

However, when such radio waves or light are used, it is necessary to communicate in a line-of-sight state due to their characteristics, and if there is a shield in the communication path, the communication quality will be significantly deteriorated or communication will not be possible. It becomes a state.

Therefore, as a system that overcomes this problem, there is a system such as the Altea J system of Motorola. The outline is shown in FIG. This system is composed of a CM 3301 which is a wireless base station and a UM 3303 which is a wireless terminal station.
A UM 3303 is arranged in a line-of-sight position, and a cable 3305 connects the UM 3303 and the terminals 3302 and 3304.

As a result, the terminal 3302 is protected by the shield 330.
4 is hidden behind the wireless base station CM 3301 and is not in the line-of-sight relationship with the base station UM 3301
The communication path between the terminal and the terminal 3302 can be secured.

However, since this system has a structure in which a fixed wireless terminal station UM and a plurality of terminals are connected by a cable, there is a problem that only fixed terminals can be accommodated.

Further, since both the downlink and the uplink communicate between the CM and UM in a line of sight in the same frequency band, when a person passes between the CM and UM and the line of sight disappears, both links are disconnected. However, there was a problem that the communication was completely disabled.

As described above, according to the conventional technology, when the millimeter wave band or the infrared ray is applied to the wireless communication, the communication quality in a place not in sight is remarkably deteriorated. Therefore, it is constructed in a room or a premises such as a wireless LAN. In such a communication system, there is a great risk that the communication path is blocked due to human activities or movement of objects, which hinders communication and becomes a major operational problem.

Further, in order to avoid this, the method of arranging the radio terminal station and the base station at the line-of-sight position and connecting the radio terminal station and the terminal via a cable remarkably hinders the mobility of the terminal. Like the above, terminals are becoming smaller and lighter, and technology is advancing in the direction of making it possible for individual people to carry it freely and use it anywhere. Incorporation is very difficult because the cable connection is a bottleneck.

Therefore, in the existing technology, it is not possible to realize a request for enabling a large amount of information to be exchanged at high speed with a wireless communication terminal, and to contactlessly communicate between the base station and the terminal. There is a strong demand for the development of a wireless communication system that enables not only the communication in the Internet but also the energy saving of the system and the realization of the data transmission at the high transmission speed.

The object of the present invention is to:
A wide bandwidth, for example, a bandwidth of 100 MHz or more can be secured to enable high-speed data transmission, and the transmission power can be reduced even if the base station side and the mobile station side are separated from each other to achieve low power consumption. The present invention is to provide a wireless communication system configured to prevent communication failures.

[0022]

In order to solve the above problems and achieve the object, the present invention is, firstly, a wireless communication system including a wireless base station, a wireless relay station and a wireless communication terminal. The downlink for information transmission from the radio base station to the radio communication terminal uses radio waves of high frequency, and the transmission is performed in a wide band via the radio relay station. The uplink for information transmission from the terminal to the radio base station uses a radio wave having a lower frequency than the downlink, and at least the radio base station side is used for transmission from the radio base station to the radio relay station. A directional antenna is used for transmission between the wireless relay station and the wireless communication terminal, and a non-directional antenna is used for transmission between the wireless relay station and the wireless communication terminal. Characterized by using a directional antenna is equal to or loose directivity of directional antennas than base station.

Second, the uplink from the radio communication terminal to the radio base station is performed without the radio relay station, and only the downlink is performed via the radio relay station, and the radio base station is used. For the downlink transmission between the wireless relay station and the wireless relay station, a directional antenna is used at least on the radio base station side, and for the downlink transmission between the wireless relay station and the wireless terminal, an omnidirectional antenna, or At least the wireless relay station uses a directional antenna with a directivity looser than the directional antenna used in the downlink between the wireless base station and the wireless relay station, and the uplink between the wireless communication terminal and the wireless base station is used. An omnidirectional antenna is used for line transmission, or a directional antenna is used for at least the radio base station.

Thirdly, it is composed of a radio base station, a radio relay station and a radio communication terminal, and communication between the radio base station and the radio terminal is a wideband downlink unidirectional line and a narrowband uplink / downlink bidirectional. , And at least a wideband downlink is performed via a wireless relay station. Among the wideband downlinks, a directional antenna is provided at least for the wireless base station between the wireless base station and the wireless relay station. In the wideband downlink, an omnidirectional antenna is provided between the wireless relay station and the wireless terminal, or at least the wireless relay station is used for the downlink used between the wireless base station and the wireless relay station. A directional antenna having a directivity looser than that of a directional antenna is used, and an omnidirectional antenna or at least a radio is used for transmission of a narrow band downlink between the wireless communication terminal and the wireless base station. A directional antenna is used for the ground station, and an omnidirectional antenna is used for uplink transmission between the wireless communication terminal and the wireless base station, or at least a directional antenna is used for the wireless base station. .

Here, an ambiguous expression of wide band / narrow band is defined. In the SDL system, the downlink transmission rate is assumed to be about 10 times the uplink transmission rate. In the present invention, the transmission rate of the wideband downlink is R1, the transmission rate of the narrowband uplink is R2, and the transmission rate of the narrowband downlink is R3, which are defined under the following conditions.

R1, R2, and R3 are not limited to fixed transmission rates and may be variable transmission rates. In any case, when R1> R2 R1> R3 holds, the transmission rate R1 is set to a wide band, The transmission rates R2 and R2 are called narrow band.

Fourth, the downlink between the base station and the relay station is connected by infrared rays, and the downlink between the relay station and the wireless terminal is connected by radio waves.

Between the base station and the terminal, there may be a wideband downlink line via the relay station and a narrowband uplink line not necessarily via the relay station, and a narrowband uplink line not necessarily via the relay station. is there.

An omnidirectional antenna is installed between the relay station and the wireless terminal, or a directional antenna is installed at least on the relay station side.

Fifth, the downlink between the base station and the relay station is connected by infrared rays, and the downlink between the relay station and the wireless terminal is also connected by infrared rays. There may be at least a wideband downlink and a narrowband uplink between the base station and the wireless terminal, and there may be another narrowband downlink.

Sixth, the broadband downlink line between the base station and the relay station is connected by infrared rays, the broadband downlink line between the relay station and the wireless terminal is connected by infrared rays, and the narrow band uplink of the wireless terminal and the base station is connected. The lines are characterized by being connected by radio waves.

[0032]

In the case of the first configuration described above, in the wireless communication system including the wireless base station, the wireless relay station and the wireless communication terminal,
At least a downlink from the radio base station to the radio communication terminal is performed via the radio relay station by a transmission medium having a wide band and a high frequency, and an uplink from the radio communication terminal to the radio base station is a downlink. The transmission medium has a band narrower than the band and a frequency lower than the frequency of the downlink.

Then, the transmission speed of the uplink from the radio communication terminal to the radio base station is slower than the transmission speed of the downlink from the radio base station to the radio communication terminal via the relay station. Therefore, only the downlink, which needs to transmit a large amount of information at high speed, has a wide band, and the uplink, which is not necessary, has a narrow band and low speed, which enables efficient use of frequencies and rationalization. Become a communication system.

That is, by adopting a communication system (SDL system) having such an asymmetrical transmission rate, only the downlink which needs to transmit a large amount of information at a high speed has a wide band and the necessity thereof is low. The uplink is a low-speed transmission in a narrow band, so that the frequency can be effectively used and a rational communication system can be realized.

Further, a directional antenna is used at least on the side of the radio base station for transmission between the radio base station and the radio relay station, whereby the transmission power is saved and the radio is transmitted. An omnidirectional antenna for transmission between the relay station and the wireless communication terminal, or a directional antenna with a directional antenna looser than the directional antenna used between the wireless base station and the wireless relay station for at least the wireless relay station. Use to reduce the adjustment accuracy of the antenna,
Moreover, the freedom of movement of the wireless communication terminal is improved.

Since a wideband downlink is required in a system such as SDL, in order to secure a wide frequency bandwidth, at least a downlink is used in a high frequency band higher than a quasi-millimeter wave band or a millimeter wave band, and infrared rays. Transmission is required.

In the present invention, the wireless relay station is installed at a position where good quality can be obtained in transmission using the millimeter wave band or infrared rays between the wireless base station and the wireless relay station. Further, the relay station is installed at a position where good quality can be obtained between the relay station and the wireless terminal.

With this installation, it is possible to maintain good quality of the broadband downlink radio line of the SDL system even when there is no line of sight between the radio base station and the radio terminal.

Regarding the downlink between the radio base station and the relay station, a directional antenna having a strong directivity is installed at least in the radio base station. The broadband downlink of the SDL system is effective for transmission at a transmission rate of 100 Mbps or more and millimeter waves. The millimeter wave band has a large propagation loss due to its high frequency. If the distance between the wireless base station and the wireless relay station is set to some extent, the base station must output a considerably large transmission power due to the extremely wide bandwidth and the size of its propagation loss. By using the directional antenna between the radio base station and the relay station, it becomes possible to dramatically reduce the transmission power of the output on the base station side.

An omnidirectional antenna is used for both the wireless relay station and the wireless terminal, or a loose directional antenna is used for the relay station side. Even if a loose directional antenna is used, take a measure such that the terminal has directivity to cover a predetermined area where the terminal may exist, or a plurality of antennas are used to cover the predetermined area. . This allows
It is possible to perform communication without impairing the mobility of the wireless terminal.

In the SDL system, the uplink from the wireless terminal to the base station is a narrow band line, and the microwave band or the like can be applied. With microwaves, it is possible to obtain a certain communication quality even outside the line of sight, so it is possible to communicate directly with the base station without going through a relay station. Even when communicating with the base station via the relay station, even if the line-of-sight between the base station and the relay station is obstructed by the passage of people, non-line-of-sight communication in the microwave band is possible. Therefore, the connection is rarely interrupted. By constructing such a system, it is possible to avoid a situation where the uplink and downlink lines are simultaneously interrupted.

Therefore, according to the present invention, 100 Mbps
It is possible to secure a bandwidth of 100 MHz or more required to obtain the transmission speed of, and it is possible to reduce the transmission power even when the base station side and the mobile station side are separated, and to achieve low power consumption. Moreover, it is possible to provide a wireless communication system having a configuration in which a communication failure is unlikely to occur.

[0043]

Embodiments of the present invention will be described below with reference to the drawings. First, the preconditions of the present invention will be described.

The present inventors have made it possible to carry out high-speed communication, to effectively use the frequency, and to make it compact and portable for the user side and practically convenient. From the perspective of enabling the use of highly functional portable wireless communication terminals, the transmission speed of the downlink from the base station to the terminal is higher than that of the uplink from the terminal to the base station by one digit or more. , Proposed a wireless communication system (SDL system) having an asymmetric transmission rate (see, for example, Japanese Patent Application No. 6-137621).

This SDL system is as shown in FIG. 1, and has a radio base station BS connected to the public network Network, and each radio base station BS has a downlink R1 having a wide frequency band and a narrow frequency band. Uplink R2 with bandwidth
With. In each radio base station BS, the radio communication terminal termin in the service area A in which communication is possible by this downlink R1
wireless communication terminals in each service area A, including mobile wireless communication terminals (mobile terminals) that can communicate with al using the downlink R1 and the uplink R2, and public networks.
Information can be exchanged with terminals and databases connected to the Network.

Here, the wireless communication terminal carried by each individual is generally a personal-use machine in which one person inputs and outputs. Therefore, a transmission capacity and a method that match the amount of information transmitted and received by one individual are required. In addition, since individual people carry it, such wireless communication terminals for individuals are naturally required to be small and lightweight, and to save power so as not to carry extra heavy batteries. To be done.

Considering the use of a wireless communication terminal carried by individuals, for example, in the case of multimedia, the terminal can watch movies, listen to music, shop, use databases, make phone calls, and write documents. Transfer, sales data and reservation data transmission, ticket reservation, acquisition of information on mass media such as magazines and newspapers (reading etc.), etc. Of these, it is necessary to send voice and documents from the terminal side to the base station Data, reservation data, commands, etc.,
These can be suppressed to several kilobits per second by using a data compression technique together, and high speed transmission is not required so much.

On the other hand, it is the image data in the case of a movie (moving image) that requires the highest speed transmission, and it is only from the base station side that such a large amount of data needs to be transmitted at a high speed. From the viewpoint of effective utilization of the frequency band, the downlink from the base station side, that is, only the downlink is wideband, and the uplink from the terminal side to the base station (uplink to the base station side is In the link, it is sufficient if a transmission line with a narrow band (that is, low speed transmission) can be secured.

Therefore, in the SDL system, as described above, the basic configuration of the wideband downlink and the narrowband uplink is adopted.

The relationship between the wireless communication base station BS and the mobile terminal capable of wireless communication in this SDL system will be described in more detail. As shown in the conceptual diagram of FIG. 2, a wireless communication base station BS and a personal portable terminal electronic device PT, which is a mobile terminal capable of wireless communication in its service area A, are
A wideband downlink R1 from the base station BS to the personal mobile terminal electronic device PT and a narrowband uplink R2 from the terminal (personal mobile terminal electronic device PT) to the base station BS are provided as radio lines between them. Therefore, it is possible to communicate with each other through these lines.

In the SDL system, information is transmitted in a wide band (for example, 100 Mbps or more) in the downlink R1. Therefore, in order to realize the SDL system by radio transmission by radio waves, it is necessary to secure a frequency bandwidth of 100 MHz or more (however, this is when multi-value modulation is not performed). The lower the frequency of the radio wave, the less likely it is to hinder communication even with the presence of obstacles, so I would like to use the low frequency band, but the low frequency band has already been assigned to various other uses. I can not use it.

Therefore, as a suboptimal measure, it is preferable to use the microwave band, but in the microwave band, it is a problem that one user occupies an extremely wide bandwidth of 100 MHz or more. , Not realistic.

Therefore, in order to secure a bandwidth of 100 MHz or more, it is necessary to use the quasi-millimeter wave band or millimeter wave band having high directivity, or to use infrared rays having no limitation on the frequency width or the like.

When the quasi-millimeter wave band, the millimeter wave band, or infrared rays are used, it is necessary to communicate in line of sight, and since attenuation also increases corresponding to the propagation distance, this is also realized from the viewpoint of energy saving. Various difficult questions remain.

Therefore, in the present invention, it is basically possible to achieve power saving on the premise that communication is performed in line of sight, and a high communication quality can be obtained while securing the degree of freedom (mobility) of the terminal. For the purpose, it was carried out as follows.

(First Embodiment) In the first embodiment, a quasi-millimeter wave or a millimeter wave is used for the downlink, and a radio relay station is interposed between the terminal and the radio base station. The wireless relay station is used for communication, and the uplink has a narrow band, so microwaves are used for direct communication between the terminal and the wireless base station.

FIG. 3 is a conceptual diagram showing the configuration of the first embodiment of the present invention.

In FIG. 3, reference numeral 1001 denotes a radio base station, 1
002 is a wireless relay station, 1003 is a mobile wireless terminal, 100
Reference numeral 4 is a downlink, 1005 is a downlink, 1006 is an uplink, 1007 is a communication area, and 1008 is a shield.

The portable radio terminal 1003 is a mobile small and lightweight radio communication terminal, and bidirectional communication can be performed by the radio base station 1001 and the downlink 1004 and the uplink 1006 which are radio lines to exchange information.

Radio base station 1001 and portable radio terminal 100
Communication line 10 using quasi-millimeter wave band or millimeter wave band between 3
Downlink line (high-speed downlink wireless communication line) 1004 with a transmission rate of 0 Mbps and 30 kbp using the microwave band
Uplink with s transmission speed (slow uplink wireless communication line) 1
So that the communication using 006 is performed.
1 and the portable wireless terminal 1003 are configured.

The downlink 1004 is a line for transmission from the radio base station 1001 to another and corresponds to R1 in FIG. 1, and is a line capable of high speed communication using a directional antenna. ing. Uplink 1006
Is a line for transmission from another to the radio base station 1001,
The line corresponds to R2 in FIG. 1 and is a line capable of low speed communication using an omnidirectional antenna.

The shield 1008 is an obstacle that obstructs communication for a communication line using the quasi-millimeter wave or millimeter wave, such as a wall or a wall, a locker or a bookcase.
Anything that blocks the line of sight will be applicable.

The radio relay station 1002 has such a shield 1
A radio base station 10 which is a relay station installed on top of 008.
01 is placed in the line of sight. Wireless relay station 1002
Has a predetermined area below as a communication area with the wireless communication terminal 1003, and 1007 is the communication area. The radio relay station 1002 is the downlink 1 from the radio base station 1001.
004 is relayed in the communication area 1007, and communication area 1
When the wireless communication terminal 1003 is in 007, the wireless communication terminal 1003 has a function of relaying the uplink 1006 from the wireless communication terminal 1003 to the wireless base station 1001. The wireless relay station 1002 is configured to transmit the downlink 1004 into the communication area 1007 in a millimeter wave band different from the downlink between the base station and the relay station.

In such a configuration, a narrow band uplink line (uplink radio communication line) 1 using the microwave band from the portable radio communication terminal 1003 to the radio base station 1001.
At 006, the transmission at the transmission rate of 30 kbps is directly performed. In the case of the microwave band, radio waves wrap around even if the line of sight is not visible, so that communication can be performed at a distance of several tens of meters without impairing communication quality.

On the other hand, for transmission from the radio base station 1001 to the radio communication terminal 1003, communication is performed using a downlink line (downlink radio communication line) 1004 using a quasi-millimeter wave band or a millimeter wave band at a transmission rate of 100 Mbps. Be seen.

The downlink 1004 is the radio relay station 100.
2 and the wireless communication terminal 1003 is in the communication area 1007, the downlink 1004 can be used with the wireless communication terminal 1003.

In this system, as described above, the downlink 10 between the radio base station 1001 and the relay station is used.
Reference numeral 04 indicates a configuration for transmission in the quasi-millimeter wave band or millimeter wave band, and a directional antenna is used as an antenna for the downlink of the radio base station 1002.

Similarly, a directional antenna is also used on the radio relay station 1002 side for receiving the downlink 1004.
When a directional antenna is used, the distribution range of the electric field strength becomes sharp. Therefore, if the transmitting and receiving antennas have the same directional direction, the transmitting side can efficiently transmit information to the receiving side with minimum power. Therefore, the receiving side can efficiently receive the information.

By using an antenna having a strong directivity, transmission power can be saved as compared with an omnidirectional antenna, but the service area is narrowed. To solve this problem, base stations may be provided at a plurality of locations, or one base station may be provided with antennas having strong directivity toward each relay station, and the antennas of these base stations may be used as antennas of the relay station. If it is directed, the downlink transmission can be made to each of the scattered relay stations.

Further, by using an antenna having a strong directivity, it is possible to provide base stations at a plurality of locations and direct the antennas of the relay stations to the base stations. In this case,
Even if the downlink of one of the base stations is blocked by a shield and the communication path is cut off, communication using the downlink of the remaining unshielded base station will be possible and a highly reliable system will be constructed. become able to.

However, if the directivity is strengthened on the receiving side, the orientation of the antenna with respect to the base station antenna must be accurately adjusted when the antenna is installed, and the adjustment becomes troublesome. Therefore, another example of solving this problem I will also show you.

The characteristics of the directional antenna that can be used in this system are shown in FIG. Figure 5
(A)-(c) shows the beam pattern of the directional antenna seen from the horizontal plane, and these are the radio base station 1
001 and the antenna pattern used in the wideband downlink of the wireless relay station 1002. For example, in the system assumed in the first embodiment, as shown in FIG. 5A, a base station (wireless base station) and 5 relay stations (wireless relay stations)
A directional antenna with a beam pattern having a beam width of about a degree is used.

Of course, the present invention is not limited to this, and as another example, as shown in FIG. 5 (b), the downlink transmission antenna on the base station side has a beam pattern orientation having a beam width of about 5 degrees. In this example, a directional antenna having a beam width of about 120 degrees, which is looser than that of the base station side, is used as the receiving antenna on the relay station side. Since the directivity is looser than that on the base station side, the adjustment accuracy of the antenna installation required on the relay station side is relaxed as compared with the previous example.

As shown in FIG. 5C, the directional antenna having a beam pattern having a beam width of about 5 degrees is used on the base station side, but an omnidirectional antenna is used on the relay station side. It is also possible to do it. In this case, although the reception quality on the relay station side is somewhat deteriorated, the adjustment accuracy of the antenna installation required on the relay station side can be completely ignored, and the installation becomes very easy.

As described above, in the system of the first embodiment, at least the directional antenna is used on the base station side. In addition, considering the degree of freedom of movement of terminals and the installation density of base stations, the base station and mobile stations (wireless communication terminals) should be configured to be able to communicate even if they are separated by a distance of several tens of meters. Therefore, it is assumed here that the distance between the base station and the mobile station is several tens of meters.

The attenuation in the millimeter wave band due to the distance propagation is large,
A very large transmission power is required to obtain a predetermined quality by radiating a distance of several tens of meters with an omnidirectional antenna. In addition, this system is intended for a wireless communication system that performs SDL transmission. Since the wireless communication system that performs SDL transmission uses a bandwidth of 100 MHz or more to realize a downlink with a transmission rate of 100 Mbps, If an omnidirectional antenna is used, even higher transmission power is required.

However, in this system, the antenna on the side of the base station is a directional antenna, the relay station 1002 is provided, and the installation position of this relay station 1002 is fixed so that the beam is sharply narrowed on the side of the base station. By doing
It is possible to dramatically reduce the transmission power.

The radio relay station 1002 is the radio base station 1
001 or line of sight, or it can be installed at a location where sufficient communication quality can be obtained. Obviously, such a position is set and installed, and line of sight in which the terminal 1003 is considered to move or sufficient communication quality can be obtained. It is installed by selecting a position that will become a place.

In this system, the wireless relay station 100
The downlink relayed in 2 is transmitted from the radio relay station 1002 to the terminal 1003, but in the radio relay station 1002, the downlink is configured to perform transmission using an omnidirectional antenna. The relay station 1002 forms a communication area 1007, which is a zone in which it can communicate with the terminal, in the area around the relay station 1002, and can communicate with the terminal 1003 in this range. In addition, of course, the terminal 1
003 uses an omnidirectional antenna to increase the degree of freedom.

As described above, in the present system, the downlink between the radio relay station 1002 and the terminal is configured to be transmitted in a millimeter wave band different from the downlink between the base station and the relay station. It is not an indispensable requirement, and of course, it does not matter if they are carried out at the same frequency.

Further, a plurality of radio relay stations 1002 can be provided, and the radio relay station 1002 is installed on the ceiling or on a stand or the like, and the distance between the relay station and the terminal in the communication area 1007 is several tens of cm to several centimeters. m, and even if an omnidirectional antenna is used for the relay station, since the distance is short, downlink transmission power in the radio relay station 1002, that is, transmission power is small, but sufficient quality can be obtained. .

The pattern of the antenna used between the relay station and the terminal is shown in FIG. FIGS. 6 (a) to 6 (d) show antenna patterns used for a broadband downlink line between a relay station and a terminal. It is assumed that an omnidirectional antenna is used on the terminal side, and the antenna pattern is described. Not not.

The above-mentioned example is shown in FIG. 6A, which is a case where an omnidirectional antenna is used for the relay station (radio relay station).
Further, in FIG. 6B, the relay station uses a directional antenna having a beam width of about 120 degrees.

As a result, the relay station can transmit with a smaller power. Also, when there are a plurality of terminals, it is possible to distinguish each terminal by the beam direction. In this case, a mechanism for detecting the position of the terminal on the relay station side is required, and the downlink may be disconnected when the terminal moves at high speed, but terminals that do not move at high speed or semi-fixed Suitable for terminals.

FIG. 6C shows an example in which the beam width of about 120 degrees covers each of the three regions.
This is called sectorization, which is a method of covering all areas with a plurality of beams. In this method, it is possible to increase the frequency utilization efficiency by dividing the communication area into a plurality of areas by sectorization.

FIG. 6D shows an example in which the area where the terminal does not exist is known in advance. If there is a region 4001 in which a terminal cannot be clearly present, such as when a direction is a wall or when there is a shelf, the beam is directed in other directions. This makes it possible to save transmission power.

In any case, compared to the case where the base station uses an omnidirectional antenna, or the case where the base station side performs sectorization and the entire range is covered by one base station, In addition, a directional antenna with a sharp beam is used between the base station and the relay station with a long distance, and an omnidirectional or loose directional antenna is used between the relay station and the terminal with a short distance of several tens of centimeters. By adopting the transmission method, it becomes possible to keep the total power low.

In this embodiment, the distance between the base station and the relay station is several tens of meters, and the distance between the relay station and the terminal (radio communication terminal) is several tens of centimeters.
However, this is only an example, and it can be said in a system where the distance is generally "distance between base station-relay station">"distance between relay station-terminal". is there. However, even if such a system configuration is adopted, it does not exclude the case where the terminal performs communication near the base station via the relay station.

As described above, the relay station for relaying between the base station and the terminal is provided to perform the downlink relay, and the transmission between the relay station and the terminal is an omnidirectional antenna or a relatively loose directivity. By adopting a configuration that uses a flexible antenna,
Even if the quasi-millimeter wave band or millimeter wave band is used for the downlink, the mobility of the terminal can be significantly improved.

The communication system based on the cable connection described in the conventional example is suitable for using a terminal whose position is fixed such that the power source is obtained from an outlet, but it is downsized and space is saved. In consideration of the widespread use of portable mobile terminals designed to meet these requirements, most of these mobile terminals use a battery-powered power supply method, and therefore, a form in which they are connected by a cable is used. Doing so is a great inconvenience because it significantly impairs the mobility.

There is also a system in which a direct directional antenna is used for transmission between a base station and a terminal without providing a relay station, but in this case, the position of the terminal must be almost fixed, and When moving, a function of tracking the position of the terminal is required, which makes it difficult to move the terminal at high speed.

However, as in the above embodiments, the base station-
When communicating between terminals, a relay station is provided in the broadband downlink, a directional antenna is used between the base station and the relay station, and an omnidirectional or loose directional antenna is used between the relay station and the terminal. The total transmission power can be dramatically reduced, and the mobility of the terminal is significantly improved.

Further, in this system, the terminal 100
The narrow band uplink 1006 from 3 to the base station 1001 is performed using the microwave band. Uplink is 30
Since the transmission speed is about kbps, it is possible to secure a sufficient bandwidth in the microwave band region. And
Since it is possible to obtain a sufficient quality in the microwave band even if it is not in sight due to its propagation characteristics, it is possible to directly transmit to the base station without going through a relay station.

FIG. 7 shows an antenna directivity pattern of the narrow band uplink between the base station and the terminal adopted in this system.
In this system, either an omnidirectional antenna is used between the base station and the terminal, or, as shown in FIG. 7A, the base station uses a plurality of beams with directivity of about 120 degrees. Sector to cover the entire area, or, as shown in FIG. 7B,
A directional antenna having a beam width of about 120 degrees is used for a specific terminal.

In any case, an antenna having a directivity less than that of the downlink antenna used in the base station is used.

Since the omnidirectional antenna is used for the uplink, the transmission power on the terminal side becomes larger than that when a directional antenna with a sharp beam is used on both the terminal side and the base station side. There is no denying it. However, the bandwidth of the uplink, which is the transmission path from the terminal to the base station, is at most 30 kbps (30 kHz), and the transmission distance is about several tens of meters. Even if the distance of about several tens of meters is directly transmitted by using the omnidirectional antenna, the power consumption of the entire terminal is not significantly increased. Therefore, it is sufficient to use a relatively loose directional antenna on the base station side.

Further, in this system, the omnidirectional antenna is used for the up-link to perform transmission in the microwave band, so that a shield appears between the base station and the relay station, and the down-link shields this shield. Even if it is blocked by an object, there is no disconnection of the uplink. Further, since the uplink is connected, the disconnection of the downlink can be notified to the base station side, so that various countermeasures for disconnecting the line can be taken.

As described above, the system shown in the first embodiment is
A radio communication system for exchanging information between a radio communication terminal and a radio base station, the radio performing SDL transmission including a downlink that performs higher speed transmission than an uplink from the radio communication terminal to the radio base station. In a communication system, at least one relay station is placed in a line-of-sight position with a base station, a millimeter wave band is used as the frequency for the downlink of the base station, and a microwave band is used for the uplink. Communication between the wireless communication terminal and the wireless base station, downlink communication from the wireless base station via the relay station, and communication from the wireless base station to the relay station via the downlink. The directional antenna is used for the transmission and reception of the downlink to the relay station and the wireless communication terminal, and the non-directional antennas are used to transmit and receive the downlink between the base station and the relay station. It was configured to perform.

As described above, the relay station is arranged in the line-of-sight position with the base station, and the terminal transmits and receives the downlink through the relay station. Therefore, even if the downlink uses the millimeter wave band. In addition to being able to perform stable communication without worrying that the line will be cut off by an obstacle, it is possible to support SDL transmission because the downlink uses the millimeter wave band, and the downlink of the base station is also available. Since the directional antenna is used for the communication, it becomes possible to transmit with a small amount of electric power even if the distance between the base station and the terminal is somewhat long. Further, since the microwave band is used for the uplink, the influence of obstacles is reduced, and therefore the uplink can directly perform communication between the terminal and the base station without going through the relay station.

That is, although the uplink uses the microwave band, the uplink has a transmission rate of about 30 kbps, so that it is possible to secure a sufficient bandwidth in the microwave band region. Since it is possible to obtain sufficient quality from the propagation characteristics of the
It is possible to transmit directly to the base station without going through the relay station.

Therefore, according to this embodiment, the downlink S
DL transmission can be performed by wireless communication, stable communication can be performed, power saving can be achieved, and a wireless communication system can be obtained in which the degree of freedom of movement of a terminal is high.

The above is the description of the basic system. Since various variations can be considered in addition to this system, an embodiment will be described below.

FIG. 4 is a block diagram schematically showing the concept of the present invention shown in FIG. The radio base station 2001 and the radio relay station 2002 are connected by a high-speed downlink line 2004 having a wide frequency band in the quasi-millimeter wave band or the millimeter wave band, and the relay station 2002 and the radio terminal 2003 are connected by a similar high-speed downlink line 2005. The terminal 2003 and the base station 2001 are directly connected by a low-speed uplink 2006. The line thickness of each line indicates high / low transmission speed.
When each line is connected by radio waves, the directivity of each antenna is in accordance with the first embodiment.

The second to sixth embodiments, which are other embodiments of the present invention, will be described below with reference to such schematic diagrams.

(Second Embodiment) In the second embodiment of the present invention, transmission of the downlink 1004 between the base station (radio base station) 1001 and the relay station (radio relay station) 1002 shown in FIG. As for the, instead of radio waves as in the first embodiment,
This is done by infrared rays. Others are the same as those in the first embodiment.

Infrared light is light, which is excellent in straightness due to its nature and is suitable for transmission between fixed stations. Therefore,
In the base station and relay station, which are fixed stations, the downlink is configured to be transmitted by an infrared beam.

In the first embodiment, since the transmission between the base station and the relay station and the transmission between the relay station and the terminal are performed at the same frequency or frequency band, there may be interference in the frequency design.

However, by using infrared rays in the downlink between the base station and the relay station as in the second embodiment, the problem can be overcome.

(Third Embodiment) A third embodiment of the present invention will be described. In the third embodiment, infrared rays are used only in the downlink 1005 from the relay station to the terminal in the configuration of FIG. Others follow the first embodiment. For infrared transmission, a method of communicating with a terminal in a zone in which infrared is scattered has been proposed (IEEE Personal Co
mmunications, Second Quart
er, PP. 12-25, (1994)).

In the case of transmission by infrared rays, the light emitted by illumination such as a fluorescent lamp becomes an interfering wave. Moreover, even if the transmission is due to scattering, it is still a condition in view as long as the communication is due to light.

The communication between the relay station and the terminal is compared with the distance from the lighting arranged on the ceiling when the relay station is installed on a table on a desk or placed on a locker or a bookcase. If it is possible to get very close, it is not easily affected by lighting. Therefore, the third embodiment can be applied to the area satisfying such conditions.

Since the relay station and the terminal can be installed at positions close to the line of sight, they are suitable for infrared transmission.

That is, as described above, in the first embodiment, there is a problem that interference may occur by using the same frequency band between the base station-relay station and the relay station-terminal. In the present embodiment, the above-mentioned problem is solved by using infrared transmission for downlink transmission between the relay station and the terminal.

(Fourth Embodiment) A fourth embodiment of the present invention will be described. This embodiment also has a configuration in which infrared rays are used in the downlink, and this fourth embodiment is based on the configuration of FIG.
A sharp beam infrared ray is used for the downlink 1004 between the relay stations, and a scattered infrared ray is used for the downlink 1005 between the relay station and the terminal.

It is unnecessary to explain that the system can be constructed with such a configuration because the fourth embodiment is a combination of the second embodiment and the third embodiment.

In the present embodiment, it is possible to construct a system that enables downlink transmission without using frequencies in the millimeter wave band. The devices for the quasi-millimeter wave band and the millimeter wave band are very expensive, and the problem of shielding for isolation between devices is serious. In addition, many of the existing millimeter-wave band devices are large in size, and terminals, relay stations,
Not suitable for downsizing and cost reduction of base stations.

According to this embodiment, by constructing each broadband downlink line by infrared rays, it is possible to realize the downsizing and cost reduction of the terminal, base station and relay station.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described. The fifth embodiment is configured such that the relay station 1002 and the terminal 1003 in the configuration of FIG. 4 are operated in a low frequency band such as a microwave band.

The line of sight between the relay station and the terminal is a line of sight, and the distance is at most several tens of cm to several m, which is a very narrow region. Therefore, for the transmission of the downlink between the relay station and the terminal, a very weak microwave band that hardly leaks outside the narrow area is used.

In this case, if it is allowed to secure a bandwidth of about 100 MHz in a low frequency band on condition that it does not leak outside, transmission is performed using that band. Also,
Since it is a line-of-sight, there is almost no fluctuation in the transmission line, and QAM
Since it is possible to use multi-valued modulation such as, it is possible to perform transmission at 100 Mbps in a narrow band using multi-valued modulation, and it is possible to perform transmission in a frequency band of microwaves.

In the case of this embodiment, since the terminal does not need to use the millimeter wave band device, it is possible to reduce the size and cost and to use different frequencies for the base station-relay station and relay station-terminal. In addition, the problem of interference between them is solved.

(Sixth Embodiment) A sixth embodiment of the present invention will be described. In the sixth embodiment, in the configuration of FIG. 4, high-speed downlink 1004 transmission from the base station to the relay station is performed by using multilevel modulation such as QAM.

The line of sight between the base station and the relay station is a line-of-sight, and they are connected using antennas having high directivity. base station-
Each relay station is a fixed station, and there is almost no fluctuation in the transmission path during this period. Therefore, weak multilevel modulation can be used for transmission line fluctuation.

By using multi-level modulation, it is possible to narrow the bandwidth to be used and lower frequency bands (for example, 12
Transmission in the GHz band or microwave band) is possible.

As a result, the base station / relay station can be downsized and the power consumption can be reduced. In addition, since the point-to-point is between the base station and the relay station, there is little leakage of radio waves to others. Therefore, the system is constructed so that even if the transmission by the microwave is performed, there is almost no adverse effect on other systems.

In the system described above, which uses a wide frequency band down line and a narrow frequency band up line, a down line uses a relay station and an up line does not go through a relay station. This is an embodiment in which infrared rays are used for downlink transmission and microwaves by multilevel modulation are used.

An embodiment in which a relay station is also involved in uplink transmission will be described as a seventh embodiment.

(Seventh Embodiment) FIG. 8 is a schematic view showing a seventh embodiment of the present invention. In FIG. 8, reference numeral 6005 is a base station (wireless base station), 6003 is a relay station (wireless relay station), 6004 is a terminal (wireless communication terminal), 6001 and 6002 are uplink channels, and 6000 is a channel.
Is a downlink. Each of these elements has basically the same function as that of each element having the same name in the first embodiment.

However, the difference between this configuration and the first embodiment is that the narrowband uplink 1006 is directly transmitted from the terminal 1003 to the base station 1001 in the first embodiment. In the example, the point is that transmission is performed via the relay station 6003. Therefore, in order to be able to implement this difference, the relay station 6003 is
The uplink 6002 from 04 is relayed to the base station 6005, and the base station 6005 is configured to be able to receive the uplink 6001 relayed by the relay station 6003.

With such a configuration, the terminal 100
3-between relay stations 6003, relay station 6003-base station 600
No. 5 is the line of sight, and it is possible to communicate on the uplink with a transmission medium that can be done only by using the line of sight such as infrared rays. Further, since the distance between the terminal and the relay station is shorter than the case where the terminal and the base station are directly transmitted, the transmission power of the terminal can be made extremely small.

In the present embodiment, when a low frequency band such as a microwave band is used for the uplink between the relay station and the base station, a shield is inserted between them and the downlink is disconnected.
It is possible to continue communication without disconnecting the uplink.

In all of the above, in a system having a configuration using a wide frequency band downlink and a narrow frequency band uplink, the downlink uses a relay station and the uplink does not pass through a relay station. Met. Therefore, when transmitting data from the base station, the downlink having a wide frequency band has to be used regardless of the amount of data and the speed required for the data. Therefore, an example of solving this will be described below.

(Eighth Embodiment) FIG. 9 is a schematic view showing an eighth embodiment of the present invention. The eighth embodiment has a configuration in which a downlink 2000 having a narrow frequency band is added as the third line. That is, the eighth embodiment is different from the first embodiment in that downlinks 1004 and 1005 that use a wide frequency band may be used, and a direct microwave or the like may not be directly projected between the terminal and the base station. Another point is that a downlink 2000 is further added by a wireless line capable of obtaining various communication qualities, and bidirectional communication in a narrow frequency band can be performed in combination with an uplink 1006 for a narrow frequency band.

In the eighth embodiment, the base station 100 is provided so that differences from the first embodiment can be implemented.
1 is configured to be able to transmit the narrow band downlink 2000 to the terminal 1003, and the terminal 1003 is configured to be able to receive the narrow band downlink 2000.

By having such a bidirectional narrow band link, even when the wide band downlink lines 1004 and 1005 are disconnected, the uplink line 100 for a narrow frequency band is used.
6 and the downlink 2000, bidirectional communication is possible, control information and the like can be exchanged, and the broadband downlink 10
When 04, 1005 are reconnected, data can be received immediately, and downlink transmission of data that does not require a high transmission rate is performed by the third line 2000, so that a wideband downlink 1004 is always available. Compared with the case of using 1005, it is possible to construct a system that can save power.

(Ninth Embodiment) FIG. 10 is a schematic diagram showing a ninth embodiment of the present invention. The ninth embodiment has the same structure as that of the seventh embodiment shown in FIG.
The narrow-band downlink 2000 and the uplink 1006 both of which are wideband downlinks 1004, 1
Similar to 005, the base station 6005 is transmitted via the relay station 6003.
It is configured to be transmitted to.

Thus, as in the eighth embodiment, the third
The narrow-band downlink 2000 directly transmitted between the terminal 1003 and the base station 1001 including the line 2000 (see FIG. 1).
0 corresponds to 2000a and 2000b), and uplink 1006 (corresponds to 6001 and 6002 in FIG. 10)
In the ninth embodiment, since the connection is made via the relay station 6003, all the lines are transmitted via the relay station together with the broadband downlink line.
Similar to the seventh embodiment, it is possible to suppress the transmission power of the terminal.

In other words, with such a configuration,
From the terminal to the relay station, from the relay station to the base station, the line of sight will be
It becomes possible to communicate with a transmission medium that can be performed only by using a line of sight such as infrared rays. Further, since the distance between the terminal and the relay station is shorter than the case where the terminal and the base station are directly transmitted, the transmission power of the terminal can be made extremely small.

In the present embodiment, when a low frequency band such as a microwave band is used for the uplink between the relay station and the base station, a shield is inserted between them and the downlink is disconnected.
It is possible to continue communication without disconnecting the uplink.

In the ninth embodiment, the relay station 6003 relays the uplink 6002 from the terminal 1003 to the base station 6005 so that the difference from the seventh and eighth embodiments can be implemented. The base station 6005 is the relay station 60
03, the base station 6005 receives the narrow-band downlink 2000a and the relay station 6 receives the uplink 6001.
003 and the relay station 6003 can be further relayed to the terminal 1003 as the downlink 2000b, and the terminal 1003 can receive the narrow band downlink 2000b. To do.

(Tenth Embodiment) FIG. 11 shows the first embodiment of the present invention.
It is a conceptual diagram which showed the Example of 0. The tenth embodiment has a configuration in which a plurality of relay stations are provided and communication with one terminal is simultaneously performed via the plurality of relay stations. 900 in the figure
1 is a base station (radio base station), 9002, 9003
Is a relay station (wireless relay station), 9008 is a terminal (wireless communication terminal), 9004 to 9006 are broadband uplinks, and 9009 is a narrowband downlink. Each of these elements has basically the same function as that of each element having the same name in the first embodiment.

However, the difference in this configuration from the first embodiment is that in the first embodiment, the transmission of a wideband downlink via a single relay station
In the embodiment of No. 0, the terminal is configured to be transmitted via a plurality of relay stations. Therefore, in order to implement this difference, the functions of the terminal including the functions described below are configured. There is.

As shown in FIG. 11, in the tenth embodiment, relay stations 9002, 90 are connected from the base station 9001 to the mobile terminal 9007 by high-speed downlink lines 1104, 1107.
03, and directly communicates from the mobile terminal 9007 to the base station 9001 via the low-speed uplink 9009.

The uplink 9009 is from the terminal to the base station 900.
1 is directly transmitted to the terminal 1, but at this time, in the uplink 9009, the terminal 9007 uses an omnidirectional antenna and the base station uses a sectorized loose directional antenna.

Downlinks 1104 and 1107 are carried out by using relay stations, but base station 9001 -relay stations 9002,9
Between 003, transmission is performed by using directional antennas with narrow beam widths on both sides. In the base station 9001, the terminal 90
08, a plurality of relay stations 9002,
Simultaneously with 9003. An omnidirectional antenna is used between the relay station and the wireless terminal.

With such a system configuration, the terminal can receive the downlink from another relay station even if the state of the transmission path with a certain relay station deteriorates and there are many errors. Therefore, good communication quality can always be maintained.

In addition, in the case of this system, it is possible to perform microdiversity by two relay stations in the downlink, and to keep the quality of the downlink between the base station and the terminal constant even if the wireless terminal moves. Is possible.

(Eleventh Embodiment) FIG. 12 shows the first embodiment of the present invention.
Example 1 will be described. The eleventh embodiment has a configuration in which the ninth and seventh embodiments are combined, and a plurality of relay stations are provided and communication with one terminal is performed simultaneously through the plurality of relay stations. However, not only the downlink but also the uplink is simultaneously configured via a plurality of relay stations.

That is, the difference between the eleventh embodiment and the ninth and seventh embodiments is that the uplink 9009 is connected to the terminal 90.
No. 03 directly connects to the base station 9001, but a plurality of relay stations 9002 and 9003 are used. Note that 9006a to 9009d are uplinks.

As described above, by adopting a system configuration in which the uplink is not directly transmitted from the terminal to the base station but through a plurality of relay stations, the diversity effect is obtained not only in the downlink but also in the uplink. Therefore, the quality of the uplink can be kept constant even if there is a change in the transmission path.

In the eleventh embodiment, the difference from the ninth and seventh embodiments can be implemented.
It is assumed that the relay station and the base station are functionally configured.

Various embodiments have been described above. In short, the present invention relays for a high speed downlink in a wireless communication system having a downlink with a high transmission rate and an uplink with a low speed between a base station and a terminal. A station is arranged, and a directional antenna is used in the downlink between the base station and the relay station, and an omnidirectional antenna is used in the downlink between the relay station and the terminal.

By adopting such a system configuration, it becomes possible to dramatically reduce the transmission power of the base station.
Further, it becomes possible to suppress the total power used for transmission of the downlink including the base station / relay station to be small. Furthermore, it becomes possible to significantly improve the mobility of the terminal. In addition, even if a person or other obstacle enters between the base station and relay station and the downlink is disconnected, communication of a certain quality can be performed without disconnecting the uplink, and control information is passed. It enables quick data transmission when the downlink is reconnected.

Further, the base station can communicate with the terminal through a plurality of links by using a plurality of relay stations, and as a result, a diversity effect can be obtained and a certain quality of communication can be maintained.

The present invention is not limited to the above-mentioned embodiments, but can be modified in various ways.

[0156]

As described above in detail, according to the present invention, a relay station is arranged for a high speed downlink in a radio communication system having a high speed downlink and a low speed uplink between a base station and a terminal. However, since the directional antenna is used in the downlink between the base station and the relay station, and the omnidirectional antenna is used in the downlink between the relay station and the terminal, the transmission power of the base station is dramatically reduced. In addition, it is possible to reduce the total power used for transmission of downlink including base stations and relay stations.

Further, it becomes possible to remarkably improve the mobility of the terminal, and in addition, even if a shield such as a person enters between the base station and the relay station and the downlink is disconnected, Enables communication of a certain quality without disconnection, and enables the transfer of control information and the quickest data transmission when the downlink is reconnected.

Further, the base station can communicate with the terminal through a plurality of links by using a plurality of relay stations, and as a result, a diversity effect can be obtained and a certain quality of communication can be maintained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention,
The conceptual diagram of the SDL system used as the premise to which this invention is applied.

FIG. 2 is a diagram for explaining an embodiment of the present invention,
The system conceptual diagram which shows one Example of this invention.

FIG. 3 is a diagram for explaining an embodiment of the present invention,
The system conceptual schematic diagram which shows the 1st Example of this invention.

FIG. 4 is a diagram for explaining an embodiment of the present invention,
FIG. 1 is a schematic diagram of a system concept showing an embodiment of the present invention.

FIG. 5 is a diagram for explaining an embodiment of the present invention,
The antenna gain pattern figure which showed the directivity pattern of the antenna used for the downlink of the base station and relay station in the Example of this invention.

FIG. 6 is a diagram for explaining an embodiment of the present invention,
The antenna gain pattern figure which showed the directivity pattern of the antenna used for the downlink of a relay station and a terminal in the Example of this invention.

FIG. 7 is a diagram for explaining an embodiment of the present invention,
The antenna gain pattern figure which showed the directivity pattern of the antenna used for the uplink of a base station and a terminal in the Example of this invention.

FIG. 8 is a diagram for explaining an embodiment of the present invention,
The system conceptual schematic diagram which showed the 7th Example of this invention.

FIG. 9 is a diagram for explaining an embodiment of the present invention,
The system conceptual schematic diagram which showed the 8th Example of this invention.

FIG. 10 is a diagram for explaining the embodiment of the present invention and is a system conceptual schematic diagram showing the ninth embodiment of the present invention.

FIG. 11 is a diagram for explaining the embodiment of the present invention and is a system conceptual diagram showing a tenth embodiment of the present invention.

FIG. 12 is a diagram for explaining the embodiment of the present invention and is a system conceptual diagram showing an eleventh embodiment of the present invention.

FIG. 13 is a system conceptual diagram showing a conventional wireless communication system using microwaves.

FIG. 14 is an explanatory diagram showing a case where millimeter waves and infrared rays are applied to a conventional wireless communication system using microwaves.

FIG. 15 is a system conceptual diagram showing a conventional wireless communication system.

[Explanation of symbols]

1001, 6005, 9001 ... Wireless base station 1002, 6003, 9002, 9003 ... Wireless relay station 1003, 9008 ... Wireless communication terminal 1008 ... Shield 1004, 9004, 9005 ... High speed downlink 2000, 2000a, 2000b ... Low speed downlink Line 1006, 6001, 60001, 6002, 9009, 9009a to 9009d ... Low-speed upstream line.

Claims (5)

[Claims] 1. A wireless communication system comprising a wireless base station, a wireless relay station and a wireless communication terminal, wherein a downlink for transmitting information from the wireless base station to the wireless communication terminal is relatively Uses high frequency radio signals, and
The transmission is configured to be performed in a wide band via the wireless relay station, and the uplink for information transmission from the radio communication terminal to the radio base station uses a radio signal having a relatively lower frequency than the downlink. In the transmission from the wireless base station to the wireless relay station, a directional antenna is used at least on the wireless base station side, and an omnidirectional antenna is used in the transmission between the wireless relay station and the wireless communication terminal, Further, at least the wireless relay station uses a directional antenna having a directivity equal to or less than that of the directional antenna of the wireless base station for receiving the downlink from the wireless base station. system. 2. An uplink from a wireless communication terminal to the wireless base station is directly configured without going through the wireless relay station, and at least the downlink is transmitted from the wireless base station to the wireless relay station. A directional antenna is used on the radio base station side, and an omnidirectional antenna is used for downlink transmission between the radio relay station and the radio terminal, or at least for the radio relay station, the downlink line between the radio base station and the radio relay station. Use a directional antenna with a directivity looser than the directional antenna used for the transmission, and use an omnidirectional antenna for both transmissions in the uplink between the wireless communication terminal and the wireless base station, or at least a directional antenna for the wireless base station. 3. The method according to claim 1, wherein
The described wireless communication system. 3. A wireless communication system comprising wireless communication terminals of a wireless base station and a wireless relay station, wherein a downlink for information transmission from the wireless base station to the wireless communication terminal is the wireless communication terminal. A first downlink having a first transmission rate at a relatively high frequency in a wide band transmitted via a relay station, and a narrow band first downlink directly transmitted from the radio base station to the radio communication terminal A second downlink having a relatively slower second transmission rate, and an uplink for information transmission from the wireless communication terminal to the wireless base station is a narrow band and has the first transmission rate. A line having a relatively slower transmission speed is used, and a directional antenna is provided at least in the wireless base station for transmission of the downlink between the wireless base station and the wireless relay station in the first downlink. Using the first For the downlink transmission between the radio relay station and the radio terminal of the downlink, use omnidirectional antennas for both, or at least for the radio relay station, the first from the radio base station. 2. The radio communication system according to claim 1, wherein a directional antenna having a directivity looser than that of the radio base station used for downlink transmission is used for downlink reception of No. 1. 4. A wireless communication system comprising wireless communication terminals of a wireless base station and a wireless relay station, wherein a downlink for information transmission from the wireless base station to the wireless communication terminal is the wireless communication terminal. A first downlink with a first transmission rate at a relatively high frequency in a wide band transmitted via a relay station, and a narrow band first direct transmission from the radio base station to the radio communication terminal And a second downlink having a relatively slow second transmission rate, wherein an uplink for information transmission from the wireless communication terminal to the wireless base station is a narrow band and has a narrower bandwidth than the first transmission rate. A line having a relatively low transmission rate is used, and a directional antenna is used at least in the radio base station for transmission of the downlink between the radio base station and the radio relay station in the first downlink. , With the wireless relay station An omnidirectional antenna is used for transmission of the first downlink with the wireless terminal, and at least the wireless relay station is used for receiving the first downlink from the wireless base station. A directional antenna having a directivity equal to or less than that of the directional antenna used for downlink transmission of the radio base station is used, and an omnidirectional antenna is used for both transmissions of the second downlink, or A wireless communication system characterized by using a directional antenna for at least a wireless base station. 5. A wireless communication system comprising a wireless base station, a wireless relay station, and a wireless communication terminal, wherein a downlink for information transmission from the wireless base station to the wireless communication terminal is of a lightwave frequency. A modulated wave is used and configured to perform wide band via the wireless relay station, and an uplink for transmitting information from the radio communication terminal to the radio base station uses a radio signal having a lower frequency than the downlink. A wireless communication system characterized by the above.